In hydraulic systems utilizing hydraulic valves for controlling the flow to an actuator such as a cylinder, it is conventional to utilize controllers which are actuated by fluid at pilot pressure to control the movement and flow to and from hydraulic valves.
The present invention is directed to an electrically controlled hydraulic remote controller which can be remotely controlled and which will function by an electrical signal from a remote source to control flow of pilot pressure to not only move the hydraulic valve into a position for operating the actuator but also control the flow of pilot fluid out of the hydraulic valve to increase the speed of response of the hydraulic valve so that the actuator which is being operated will move more quickly.
In accordance with the invention, the electrically controlled hydraulic remote controller for use in piloting the operating of a hydraulic control valve comprises a pair of electrically operated three-way pressure control valves. Each control valve has a supply pressure inlet and a controlled pressure outlet operable in the de-energized position to prevent flow from the supply inlet to the controlled pressure outlet and connect the outlet to tank. The valve when energized is operable to permit fluid to flow from the inlet to the controlled pressure outlet, the pressure at the outlet being proportional to the electrical current operating the valve and simultaneously permitting fluid to flow to tank. The system includes means responsive to the higher of the controlled pressures at the outlets of the two pressure control valves for applying the higher controlled pressure to the control valve having the lower controlled pressure to operate the valve having the lower controlled pressure in a direction increasing the passage of fluid from a hydraulic valve being controlled through the valve having lower controlled pressure to tank.